I stopped by my local outdoors store tonight and they had some boots on sale for 50% off. I bought the Salomon X-Adventure 8 (hefty, SNS-BC) and Madshus Vidda (light, NNN-BC) with the intention of trying them on at home and returning one of them.

Well, they both fit really well and I'm tempted to just keep them both. I don't yet have any BC skis, but would prefer to stick with 1 binding system if I can.

Looking at the bottoms, it seems that the SNS-BC would fit the NNN-BC binding if I just carve out the two grooves. The bars look pretty much identical and are the same height. The only other difference is the toe of the NNN-BC boot seems to protude out a bit more.

Has anyone done this? I've attached a photo, the SNS-BC are on the left and the NNN-BC on the right.

All I can say is good luck... The brands do everything in their power to stop them from being compatible with each other, so I doubt it will work, but you never know. If you have any warranty issues, you will be in trouble though.

Turns out the Salomon boots didn't fit so well after all. I kept them on for a few minutes one day and noticed that the heel portion was too narrow and after about 5 min my arches started to hurt. If this happened while sitting on the couch, I doubt it will be better on the trail.